Continuous steel casting apparatus

ABSTRACT

In a method of casting of steel by pouring it in the molten state from an oblique spout onto a parallel, oblique mold which has two sections, individually moving along a path which, after separating from the path of the solidified billet, return to the original point, an apparatus is provided which includes a cooled ingot mold longitudinally divided into two sections, a container to feed molten steel from a lower curved spout and means for moving forward a first section of the mold on a preestablished path to lower it and to carry it back again behind a second section of the mold and in alignment therewith.

United States Patent 11 1 Brusa Aug. 7, 1973 CONTINUOUS STEEL CASTING 2,091,348 6/1921 196169716 164/279 x APPARATUS FOREIGN PATENTS OR APPLICATIONS [761 lnvenm Bmgms, 713,979 7/1965 Canada 164/279 Domodossola, Italy 1,810,123 8/1969 Germany 164/279 [22] Filed: Jan. 3, 1972 y Primary Examiner-R. Spencer Annear 21] Appl 214328 An0rney-Clario Ceccon Related US. Application Data [63] C0ntinuation-in-part of Ser. No. 796,120, Feb. 3,

1969, abandoned. [57] ABSTRACT In a method of casting of steel by pouring it in the mol- [30] Foreign Application Priority Data ten state from an oblique spout onto a parallel, oblique Feb. 6, 1968 Italy 50417 A/68 which has sectims mdividuany "Wing almg July 30, 1968 Italy 52642 A/68 a P which after separating mm the P lidified billet, return to the original point, an apparatus 52 us. Cl. 164/276, 164/279 is P which includes a cooled ingot "101d longitu- 51 Int. Cl 322d 11/06 finally divided Sections, a container to feed [58] Field 6: Search 164/82, 87, 276, molten Steel P and means 164/279 moving forward a first section of the mold on a preestablished path to lower it and to carry it back again be- [56] References cu hind a second section of the mold and in alignment UNITED STATES PATENTS 1,928,562 9/1933 Harbord et a]. I64/279 4 Claims, 14 Drawing Figures CONTINUOUS STEEL CASTING APPARATUS This application is a continuation-in-part of application Ser. no. 796,120, filed on Feb. 3, 1969 by the same applicant and now abandoned.

The present invention relates to apparatus for the continuous casting of steel.

Known methods and apparatus for the continuous casting of steel consist in the pouring of liquid steel into a vertical copper ingot mold which is water cooled.

The early attempts utilized a stationary ingot mold and, under those conditions, the rate at which the solidified billet could be drawn off was extremely low, usually of the order of about 2 cm per second.

Subsequently, ingot molds, which were moving alternately and vertically, were adopted. This helped. the cooling of the billet and allowed an increase in the drawing speed to about cm per second without usually incurring in any breakage of the billet.

Therefore, according to known techniques, the production of a daily quantity of billets suitable for industrial scale, requires the installation of several working lines and hence high installation and operation costs.

These expenses are further increased by the necessity of extending considerably the height of the installation and of providing it with means suitable to produce the ingot mold oscillation.

Another inconvenience of the known methods and apparatus is that, at the present time, the billets produced on an industrial scale are billets having only rectangular or square cross-section.

It is, therefore, an object of present invention toprovide improved apparatus for the continuous casting of steel billets which eliminatesthe aforesaid drawbacks, making possible a high production for each'working line.

It is another object of the inventionto provide apparatus that makes possible the continuous casting of billets of any cross-section desired.

The apparatus according tothe invention, comprises substantially a cooled ingot mold, divided in its longitudinal direction into two sections; a container used as a ladle and sometimes called tundish" that is provided with a lower curved spout and mechanical means to move forward one section of the ingot mold into a preestablished position, to then lower it and then to bring it back up-stream from the other section and in alignment therewith.

In other words, the two sections of the ingot mold, which may for example have their ends shaped to fit one another alternately under the spout, move together for a given distance until the downstream section, being in contact with already solidified steel, disengages from the billet and travels again upstream to renew the cycle.

In a first embodiment of the invention said sections of the ingot mold are open upwardly and the one of them which is in contact with molten steel is provided with a fixed cover or lid which does not move together withthe ingot mold.

In another embodiment, each section of the ingot mold is open upwardly and cooperates with a cover which does not participate in the translational movement of the assembly, but consists of a structure shaped like a track which permits it to slide at the same speed as the steel in contact therewith.

Preferably, the two sections of the ingot mold. are each mounted on a supporting structure in such a way as to be initially subjected to a traction in a longitudinal direction. The stresses due to heating are thus neutralized and distortions are minimized.

In still another embodiment of the invention, the ingot mold is provided with a narrow upper slit, sufficient to permit the passage of the spout and provided with aplug of the corresponding cross section.

According to a preferred embodiment, the plug and- /or one or more of the ingot mold walls are constructed with grooved plates to allow the circulation of cooling water, the plates having ribs wherein the ends of bolts, whose nuts bear on the surface of a considerably thicker block, are screwed, in order to minimize distortions due to temperature.

In another embodiment, the ingot mold is provided with a lid which is moved forward: at the same speed as the solidified billet. Thus the sliding of the steel against the lid isavoided, along with savings in power, and lid wear and better surface conditions of the finished billet.

Moreover, the steel is also water cooled through the lid which is hollow and divided in a plurality of sections.

In this last mentioned embodiment, each ingot mold section has a longitudinal pin on which a lid, divided into a plurality of sections, is pivoted. The lid sections are arranged side-by-side to one another and may be moved from the open position to the closed position, for example, by automatic means.

Other particular features and advantages of the present invention will become clearly understood from the following description and from. the accompanying drawings, wherein:

FIG. I is a schematic side view of a preferred embodiment of the apparatus according to the invention;

FIG. 2 is a simplified cross sectional view of the apparatus of FIG. 1; I

FIG. 3 is a cross sectional view of the ingot mold according to a first variant of the apparatus;

FIG. 4 is a cross sectionalview of an ingot mold and of the lower part of the ladle in a variant of FIG. 3;

FIG. 5 is a section of the ribbed structure of the lid and/or wall of the] apparatus of the invention;

FIG. 6 is a perspective view of still another embodiment of the ingotmold;

FIG. 7 is a schematic assembly :for the ingot FIG.6; t H.

FIG. 8 and 9 represent perspective and side views, respectively, of a further construction of the ingot mold; l

FIG. 10 is a schematic drawing of the construction of the lid; i 7

FIG. 11 is a perspective view of an installation according to a further, preferred embodiment of the invention;

FIG. 12 is a schematic side view of the installation of FIG. 11, in working position;

FIG. 13 is a view similar to FIG. 12 but illustrating a different working phase; and

FIG. 14 is a schematic end view of the apparatus of the invention.

mold of With reference to FIG. I of the drawings, the apparatus according to the invention comprises an ingot mold formed by two section 1A and 1B carried respectively by arms 2A, 3A and 2B, 3B.

The ingot sections 1A and 1B are made of copper with the bottom and side walls provided with recesses cooled by means of circulating water entering from an pipe inlet 4 and exiting from a pipe outlet 5. The inlet 4 and the outlet 5 are, in turn, connected with pipes 6 and 7, which terminate on drum 8.

For the sake of simplicity in the drawings, these cooling means have been represented for section 18 only, although also section 1A is provided with analogous means.

Arms 2A, 3A and 2B, 3B are pivotably connected to a frame 9A or, respectively, 98 which are provided with wheels 10A, 11A or, respectively 1013, 113 which slide on rails 12.

As more clearly shown in FIG. 2, the ingot mold sections 1A and 1B are carried by arms 3A and 3B positioned on opposite sides with respect to the longitudinal center axis of the apparatus.

In FIG. 1, there is also shown part of a ladle 13 the bottom of which is provided with a curved spout 14 for the withdrawal of a jet parallel to the direction of flow, that is, parallel to the rails 12.

The ingot mold may be constructed in several ways.

In the case of the embodiment shown in FIG. 3, the ingot mold is a cross-sectionally U-shaped vessel with hollow walls, against which a hollow, water-cooled lid 15 is resting. From FIG. 1, it may be clearly seen that this lid 15 is somewhat shorter than the ingot mold 1A so as to leave a free passage for the steel jet or, respectively,for the ladle spout 14.

In the case of the embodiment shown in FIG. 4, the ingot mold has a cross section of an almost completely rectangular shape, and is provided with a narrow aperture having outwardly sloping edges, to form the seat for a lid 16 of conjugate shape.

One advantageous construction for the lid or for one or more of the walls of the ingot mold, is represented in FIG. 5. A plate 17 is provided therein with very deep and parallel grooves 18 leaving a thin wall 19 as the bottom of grooves 18. The grooves are closed on top by a block 20 crossed by a set of bolts 21 that are fastened to the ribs 22 flanking the grooves 18.

It may be desirable to mount each section 1A, 1B of the ingot mold in such a way as to submit it to a longitudinal tension.

In FIG. 6 there is shown a thin wall positioned between two channeI-shaped heads 23, 24 which are tight-fitted on a frame 26, as also shown in FIG. 7.

The same result may be obtained with the mechani cal means shown in FIGS. 8 and 9. In this case, between the heads 23 and 24 there is arranged a certain number of thrust units or groups formed by two pins 27, 28 which may telescope one within the other and counteract the action of a strong compression spring 29.

FIG. 10 illustrates a construction of the lid 10 wherein friction due to contact with the steel dropping in the ingot mold is avoided.

A tracked belt 32 slides around two rollers 30, 31 at least one of which is driven by a motor. Pipes 33 for spraying water upon the lower section of the belt contacting the steel, are provided in the innerside of the band path.

The molten steel drops from the spout l4 and enters the ingot mold section which is directly under the cover or lid 15. The steel cools upon contacting the walls and solidifies and then exits from the ingot mold in the solid state and is deviated along the path defined by rollers 34, 35 which move it forward towards a suitablecutting means (not shown).

Section 18 of the ingot mold which is no longer in contact with the billet, lowers and, by means not shown in the drawings, is returned to the original upper position along the corresponding rail 12, travelling beyond section 1A. When raised again to the level of section 1A, it takes its place at the beginning of the descent.

In the embodiment illustrated in FIGS. 11 to 14, the two sections 1A and 1B of the ingot mold are provided with means which permit their sliding movement on rails 51, 52.

Said means consist of members 50 supporting said ingot molds and provided with wheels 62 engaging rails 51 and 52. To the shaft connecting the wheels of one of said support members 50 is connected a gear 63 meshing with a fixed rack 64: gear 63 is driven by a motor mounted on a bracket 66 carried by said one member 50.

The upper part of each section of the ingot mold is provided with a lateral pin 53 on which a number of lid sections 55 are pivotally mounted through a sleeve 54 to form a cover which may close the upper end of the ingot mold. To this end, each lid section may be moved from a closed position, indicated at 55, to an open position indicated at 55', or vice versa.

Preferably, the closing motion of the various lid sections is effected, at a suitable time, automatically, such as, for instance, by contact with a shaped plate 56, fixedly positioned with respect to the apparatus frame. Pin 53 and lid sections 55 are hollow and water cooled.

Also the opening motion of the various lid sections may be effected automatically at the suitable time such as, for instance, by contact of a pin 67 that is secured to each lid section with a guide 68 fixedly positioned with respect to the apparatus frame.

The lid sections 55 are kept closed by pressure wheels 69 which oppose the ferrostatical pressure exerted by the molten steel.

A ladle 13 with spout 14 is fixedly supported above the ingot mold 1A. Sliding rails 51, 52 are integrally connected with pairs of vertical plates 57 and 58 respectively, pivoting on a pin 59 and located under the action of their respective jacks 60 and 61. Also rack 64 is integrally connected with vertical plates 57, 58.

FIGS. 12 to 14 show also flexible pipes which lead to the ingot molds and to the covers the cooling water coming from a reservoir 71.

The operation of the apparatus according to this embodiment of the invention is as follows:

To start, the two ingot mold sections are aligned and in end-to-end contact with each other. Plates 57 and 58 are positioned with their upper edges parallel to one another and hanging to the left (FIG. 12), that is, the pistons of jacks 60 and 61 are in the position of maximum extraction. The lid sections are in the raised position. The flow of the molten steel contained in the ladle 13 is initiated and the steel falls in the underlying ingot mold section 1A while being cooled at contact with the cooled mold bottom and walls. The steel solidifies while it is falling and the ingot mold is concurrently moved down at the same speed by motor 65 which drives gear 63 meshing with rack 64. As the lid sections 55 move past the shaped plate 56, they are overturned into position 55, thus closing the upper end of the ingot mold. Pressure wheels 69 keep the lid sections closed during the cooling of the four faces of the solidified billet which cooling is therefore achieved in an even and symmetrical manner. When the steel is solidified, the

lid sections 55 are opened by the action of pins 67 sliding on guide 68 and the billet is diverged towards a cutting device (not shown). The mold section which is in the forwardmost position leaves the billet and is caused to slide in the opposite direction. This movement is achieved by withdrawing the piston within the jack 60, so as to bring plate 57 in horizontal position, and then operating motor 65. When the ingot mold has almost reached the end of plate 57, the latter is again raised and the cycle is repeated.

What is claimed is:

1. Apparatus for continuously casting steel ingots, said apparatus comprising first and second cooled ingot molds, container means for feeding molten steel successively into said first and second ingot molds and means for moving said first ingot mold away from said container after said first ingot mold is filled and for replacing said first ingot mold with said second ingot mold, said moving means comprising plates for slidably supporting said ingot molds, means for pivotally supporting said plates about a horizontal axis, jacks adapted to pivot said plates about said axis, a support member means secured to each said ingot mold, motor means secured to said support member means of each said ingot mold, each said motor means including an output pinion and a fixed rack integrally connected with each of said plates, said racks being in meshing engagement with respective ones of said pinions.

2. The apparatus in accordance with claim 1, wherein each said ingot mold is comprised of a thin walled, elongated central section, enlarged heads at the opposed ends of said central section and means for subjecting said central section to tension forces.

3. The apparatus in accordance with claim 1, wherein there is further provided a lid for covering said ingot molds, said lid having cooling means therein defined by a rib-like structure and bolts for subjecting said lid to tension.

4. The apparatus in accordance with claim 3, including pin means for pivotally supporting said lid with respect to said ingot molds whereby said lid is movable between open and closed positions over said ingot molds. 

1. Apparatus for continuously casting steel ingots, said apparatus comprising first and second cooled ingot molds, container means for feeding molten steel successively into said first and second ingot molds and means for moving said first ingot mold away from said container after said first ingot mold is filled and for replacing said first ingot mold with said second ingot mold, said moving means comprising plates for slidably supporting said ingot molds, means for pivotally supporting said plates about a horizontal axis, jacks adapted to pivot said plates about said axis, a support member means secured to each said ingot mold, motor means secured to said support member means of each said ingot mold, each said motor means including an output pinion and a fixed rack integrally connected with each of said plates, said racks being in meshing engagement with respective ones of said pinions.
 2. The apparatus in accordance with claim 1, wherein each said ingot mold is comprised of a thin walled, elongaTed central section, enlarged heads at the opposed ends of said central section and means for subjecting said central section to tension forces.
 3. The apparatus in accordance with claim 1, wherein there is further provided a lid for covering said ingot molds, said lid having cooling means therein defined by a rib-like structure and bolts for subjecting said lid to tension.
 4. The apparatus in accordance with claim 3, including pin means for pivotally supporting said lid with respect to said ingot molds whereby said lid is movable between open and closed positions over said ingot molds. 